Polyphenylene ether (also referred to as polyphenylene oxide or PPO) resins are known in the art as a class of thermoplastics which are characterized by excellent physical properties, including hydrolytic stability, dimensional stability and excellent dielectric properties. In general, they are prepared by the oxidative coupling of a phenolic compound with complex metal catalysts, e.g., a complex copper catalyst. The preparation of polyphenylene ether resins is described in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,875 and U.S. Pat. Nos. 3,257,357 and 3,257,358 of Stamatoff, the teachings of which are incorporated herein by reference.
The high molecular weight polyphenylene ethers are high performance engineering thermoplastics possessing relatively high melt viscosities and softening points, that is, in excess of 250.degree. C., and are useful for many commercial applications requiring high temperature resistance including formation of film, fiber and molded articles.
Cisek, U.S. Pat. No. 3,383,435, which is incorporated herein by reference, discloses polyphenylene ether/styrene resin compositions including rubber modified styrene resin-polyphenylene ether resins wherein the rubber component is of the unsaturated type such as polymers and copolymers of butadiene. Although the styrene resin component improves the moldability of the polyphenylene ethers, these compositions are still difficult to process. Polyphenylene ether/styrene resin blends comprising between about 25 and 75% of polystyrene units are available commercially from the General Electric Company under the NORYL trademark.
Uses and applications of polyolefin resins are known in the art. For example, such uses and applications are discussed in G. Hawley, Condensed Chemical Dictionary, 10th Edition (1981), p. 17 (polyacrylate and polymethacrylate esters); p. 435 (ethylene-propylene and ethylene-vinylacetate copolymers); p. 829 (polyisobutylene); pp. 830-831 (polyethylene); p. 835 (poly-4-methylpentene-1); p. 837 (polypropylene); p. 840 (polyvinyl alcohol and polyvinyl acetate).
The preparation and description of polyolefin resins are also known in the art, and are discussed, e.g., in the Encyclopedia of Polymer Science and Engineering, 2nd Edition, Vol. 1 (1985), pp. 236-305, (polyacrylate and polymethacrylate esters); Vol. 6 (1986), pp. 383-521 (polyethylenes); pp. 408, 421-422 (ethylene-polyvinyl acetate); pp. 522-564 (ethylene-propylene copolymers); Vol. 8, pp. 423-448 (polyisobutylene); Vol. 9, pp. 707-718 (poly-4-methylpentene-1); Encyclopedia of Chemical Technology, 3rd Edition, Vol. 23 (1983), pp. 817-865 (polyvinyl alcohol and polyvinyl acetate).
The preparation and description of polyethylene terephthalate resins are discussed in Encyclopedia of Polymer Science and Engineering, 2nd Edition, Vol. 12, pp. 217-256.
The uses of brominated and/or chlorinated compounds by themselves or in combination with other materials such as organic phosphates, boron compounds, etc., as flame retardants for polyphenylene ether resin compositions are well known in the art and are exemplified by U.S. Pat. Nos. 3,257,357; 3,639,506; 3,733,307; 3,809,729; 3,867,336; 3,919,356; 3,936,414; 3,974,235; 3,939,531; 4,024,093; 4,034,136; 4,073,772; 4,094,856; 4,096,117; 4,107,232; 4,191,685; 4,203,931, 4,206,154; 4,274,998; 4,280,951; 4,298,514; 4,301,062; 4,355,126; 4,403,057; 4,446,272; and 4,456,720. The aforesaid patents are incorporated herein by reference.
Further, tetrahalophthalate esters have been used as flameproofing materials. For example, U.S. Pat. No. 4,098,704 describes the use of these materials as textile finishing agents. U.S. Pat. Nos. 4,298,517 and 4,397,977 disclose these compounds as flame retardants for halogenated resins. However, prior to the inventions of the above-related applications of Lovenguth, it was unknown to use these compounds as flame retardants or processing aids for polyphenylene ether resins.
Polyhalophenyl esters have been used as flame proofing materials either as additives to plastics or incorporated as part of the polymer backbone. Examples of the latter are polyhalophenyl esters of polymerizable acids such as 2,4,6-tribromophenyl methacrylate, pentabromophenyl methacrylate, 2,4,6-tribromophenyl acrylate, pentachlorophenyl methacrylate, pentabromophenyl acrylate, trichlorophenyl acrylate, tetrabromoxylylene di(methacrylate), etc., which are exemplified by U.S. Pat. Nos. 3,207,731; 3,210,326; 3,845,102; 3,932,321; 4,032,509; 4,048,263; 4,105,628; 4,108,943; 4,110,296; 4,205,153; and 4,415,704, the disclosures of which are incorporated herein by reference.
Examples of polyhalophenyl esters that have been used as additives to plastics are pentabromophenyl 2,4,4,4-tetrachlorobutyrate, bis(2,4,6-tribromophenyl) tetrachloroterephthalate, pentabromophenyl o-(2,4,6-tribromophenoxymethyl) benzoate, pentabromophenyl o-(pentachlorophenylthiomethyl) benzoate, bis(2,4,6-tribromophenyl) isophthalate, bis(pentabromophenyl) terephthalate, 2,4,6-tribromophenyl 3,5-dibromobenzoate, 2,4,6-tribromophenyl tribromopivalate, pentachlorophenyl tribromopivalate, bis(2,4,6-trichlorophenyl) phthalate, bis(2,4,6-tribromophenyl) phthalate, pentachlorophenyl acetate, bis(2,4,6-tribromophenyl) sebacate, and pentabromophenyl acetate, etc., which are exemplified by U.S. Pat. Nos. 3,275,578; 3,660,351; and 3,804,885 as well as Eur. Pat. Appl. EP73539; Japan Kokai JP 55/56140; 53/120755; 51/86554; 51/23545; 50/90639; 50/95353; 50/87146; 48/101443 and 47/46478; and Ger. Offen. DE 2,554,513 and DE 2,161,526, the disclosures of which are incorporated herein by reference. However, no teachings have been found which show the use of these compounds as flame retardants or processing aids for polyphenylene ether resins or PPO resin blends.
Halogen-substituted polyesters have also been used as flame proofing materials. They have been prepared by either (a) the reaction of one or more at least partially halogenated dicarboxylic acids or anhydrides with a compound or compounds containing at least two hydroxyl groups or (b) the reaction of an at least partially halogenated dicarboxylic acid anhydride with one or more epoxides in the presence of a variety of catalysts. Examples of the former have been disclosed in the following patents, which are incorporated herein by reference: U.S. Pat. Nos. 2,871,215; 2,912,409; 2,913,428; 3,094,506; 3,109,831; 3,019,833; 3,196,190; 3,285,995; 3,333,022; 3,573,215; 3,585,185; 3,639,541; 3,642,724; 3,793,293; 3,929,866; 3,989,653; 4,013,815; 4,376,837; 4,555,366; Canadian Patent 741,390 and British Patent 988,304. Examples of the latter are the following, which are incorporated herein by reference: U.S. Pat. Nos. 2,589,513; 2,935,492; 3,251,903; 3,254,057; 3,565,812; 3,845,022; 3,891,596; 3,979,368; 4,430,247; and 4,555,366.
However, in general these compounds have been mixed polyesters in which halogenated acid components have been mixed with non-halogenated acid components (e.g., dicarboxylic acids or phthalic or maleic anhydrides) to improve flame retardancy of the resulting esters. Moreover, to applicant's knowledge, there has been no reference to the use of these compounds as flame retardants for polyphenylene ether resins or PPO resin blends.
Halogen substituted phthalimides have also been used as flame-proofing materials. For example, U.S. Pat. No. 3,873,567 describes the use of these materials as flame retardants in polymers, etc., especially polypropylene. U.S. Pat. No. 4,374,220 describes the use of halosubstituted mono- and bis-phthalimides for polyethylene, polypropylene, ethylene-propylene copolymers, etc. British Patent 2,114,127 describes carbonate-substituted polyhalophthalimides as flame retardants for polyethylene, among others.